At the present time, a great number of automobiles are being driven in the downtown area of large cities, and the number of automobiles is increasing rapidly day by day. But the available parking systems cannot accommodate the growing number of automobiles, which makes traffic jams at the center of these cities even worse. These problems are caused by the need for a large number of parking spaces at the limited space in the center of the city, and the high cost to install a parking system because of the very high price of real estate. To overcome these problems, solid buildings have been constructed which are used exclusively for parking. However, it is necessary for these solid buildings to occupy a large space, and they require a very high cost for equipment. In the system of solid buildings, because of the problem of driving within the building, each automobile must move to a parking position in the interior of the building, eventually resulting in aggravating traffic jams within the building itself.
Also, an apparatus is known which is used to park several automobiles vertically in the parking space of only one automobile. This apparatus is made from shaped steel usually constructed as the piling up type. This apparatus is equipped with a separate elevator for each vertical column, the elevator being used to lift an automobile placed in a suitable position. Because each vertical column of a parking system of the piling up type must be equipped with an elevator, a large space and a high initial investment for equipment cost is needed. This piling up type system eases the traffic jams at the center of the city somewhat, but eventually, it is not more helpful for solving a traffic problem than the solid building described above.
Also, there is a parking apparatus of the circulation type, which comprises multiple rectangular cages centered on a supporting bar. As said cage circulates continuously on a circle of a rectangular type, many automobiles can be deposited. Accordingly, as a parking installation, many automobiles can be parked in a minimal amount of space.
But, there are problems with the circulation type apparatus. If one wants to deposit an automobile or take an automobile out of the cage sometime after being deposited, at of the cages must be circulated until the particular cage needed is moved to the entrance. Therefore, extra safety devices must be included, in view of the large amount of circulation of each cage, thereby increasing the investment for equipment. Also, at the present time, a great number of automobiles must be parked on the limited space; therefore, the circulation method is not sufficient because only a limited number of cages may be centered on the supporting bar.